As bus speeds for printed circuit boards increase, signal referencing becomes a greater concern. For example, an open ground pin for a surface mounted connector may result in a high frequency return current path discontinuity. Thus, when a printed circuit board is manufactured, it is often desirable to validate the connections on the printed circuit board. Consistent impedance paths should be provided along routing channels, for both the printed circuit board and its surface mounted connectors. For surface mounted connectors, an unconnected ground return pin may present a deviation in impedance that may be undetectable with a shorts test and may require a specific bit pattern as an input to the printed circuit board to reveal the deviation. The difficulty of detecting open ground pin connections may be increased by the location of signal and ground pins underneath a surface mount connector, where they are not accessible to a probe. Further, in an implementation where all ground pins for the printed circuit board are connected, either via the connector itself or via a DC connection on the printed circuit board, an open ground pin cannot be electrically isolated.